I'm subscribed to Vsauce
Also minutephysics is quite interesting and cool
Ah, yes, that one is also very nice; forgot about it.
Then, there are always sites like
http://topdocumentaryfilms.com/, that keep a large collection of documentaries; problem is it doesn't help a lot in finding the interesting ones.
In relation to ALToids' Cosmos recommendation, I'd personally check the original series first (the one with Carl Sagan), if you haven't already.